Abstract

Using the full three-dimensional classical ensemble model, we have investigated nonsequential triple ionization (NSTI) of Ne by intense linearly polarized laser fields systematically. Trajectory back analysis enables us to identify the various NSTI channels at different intensities in an intuitive way. The momentum distributions of the triply ionized ions calculated by this model agree well with the experimental results over a wide range of laser intensities [J. Phys. B 41, 081006 (2008)]. With this classical model we achieve insight into the complex sub-laser-cycle dynamics of the correlated three electrons in NSTI.

The two-dimensional (the left column) and the longitudinal (the right column) momentum distributions of Ne3+ ions. The laser intensities are (a) and (b) 1.0 PW/cm2, (c) and (d) 2.0 PW/cm2, (e) and (f) 4.0 PW/cm2, respectively. The distributions are plotted in units of
Up
. The ensemble sizes are 4 million (1.0 PW/cm2), 2 million (2.0 PW/cm2) and 0.8 million (4.0 PW/cm2). For the two-dimensional momentum distributions, the horizonal axis denotes the longitudinal momentum and the vertical axis denotes the perpendicular momentum (along y axis). The data are integrated over the other perpendicular momentum component.

Triple ionization phase tTI versus recollision phase tr (both in cycle) where the intensities are (a) 1.0 PW/cm2, (b) 4.0 PW/cm2, (c) and (d) 2.0 PW/cm2, respectively. At 1.0 PW/cm2 most of the TI trajectories are ionized through (0-3) channel and at 4.0 PW/cm2 they are ionized through (0-1-3) channel. For 2.0 PW/cm2 we have separated the TI trajectories base on whether they get ionized through (0-3) (c) or (0-1-3) (d) channels.

The longitudinal ion momentum distributions of the (0-1-3) (blure curve) and (0-3) (red curve) trajectories at 2.0 PW/cm2. The black curve displays the ion momentum distribution of the total TI trajectories. The counts are divided by the total number of the TI trajectories to give the probabilities shown here.

Correlated electron momenta in the direction parallel to the laser polarization for TI of Ne. Plots (a)–(d) correspond to the trajectories in figs. 4(a)–4(d), respectively. For the trajectories in (a) and (c), three electrons are involved in recollision. However, we only display the momenta of two arbitrary electrons from the three-electron recollision. For the trajectories in (b) and (d), two electrons are involved in recollision, and the longitudinal momenta of these two electrons are shown.